Prusa Research i3 MK2 User manual

Please always refer to the http://www.prusa3d.com/drivers/
for an updated version of this Multi Material handbook (PDF download).
Original Prusa i3 MK2 Multi Material v0.9 from July 7, 2017. © Prusa Research s.r.o. 

Abouttheauthor
Josef Prusa (born Feb 23rd, 1990) became interested in the 3D printing phenomenon before
joining the Prague’s University of Economics in 2009 - at first it was a hobby, a new
technology open to changes and improvements. The hobby soon became a passion and
Josef grew into one of the leading developers of Adrien Bowyer’s international, open source,
RepRap project. Today, you can see the Prusa design in different versions all around the
world, it is one of the most popular printers and thanks to it, knowledge about the 3D printing
technology significantly increased among public.
Jo’s work on self-replicating printers (you can print the other printer parts with your printer)
are still ongoing and currently there is Prusa i3 - the third iteration of the original 3D printer. It
is constantly updated with the latest innovations and you've just purchased its latest version.
In addition to printer hardware upgrades, the main goal is to make the technology more
accessible and understandable for all users.
Josef Prusa also organizes workshops for the public, participates in professional
conferences dedicated to the popularization of 3D printing. For example, he lectured at the
TEDx conference in Prague and Vienna, at World Maker Faire in New York, Maker Faire in
Rome or at the Open Hardware Summit hosted by MIT. Josef also teaches Arduino at
Charles University and was also a lecturer at the Academy of Arts in Prague.
In his own words, he imagines 3D printers will be available in every home in a not too distant
future. If anything is needed, you can simply print it. In this field, you just push the
boundaries every day... We're glad you're part of it with us!

Tableofcontents
About the author 3
2 Product details 5
3 Multi Material Upgrade introduction 5
3.1 How it functions 5
4 Software 6
4.1 Prusa3D Slic3r Multi Material 6
4.1.2 Slicing profiles 8
4.2 Multi Material post processor 8
5 Supported materials 9
5.1 Filaments and print quality 10
5.2 Loading/Unloading the filament 10
6 Upgrade and first print 11
7 Printing in Multi Material mode 11
7.1 Loading the model in Slic3r Multi Material 11
7.2 Printing with soluble supports 13
8 Printing in Single mode with one extruder 14
8.3 Using web Color Print app 14
9 Frequently asked questions 15
9.1 Smart Wipe Tower size and additional print time 15
10 Troubleshooting 18

Important notice, tip, hint or information that helps you print with ease.
Read carefully! This part of text has uppermost importance - either for user safety of
for a proper printer service.
This symbol indicates text related to printer kit only.

2Productdetails
Title: Multi Material Upgrade for Original Prusa i3 MK2/MK2S / Original Prusa i3 MK2/MK2S
(kit)
Manufacturer: Prusa Research s.r.o., 188/7a Partyzanska, Prague, 170 00, Czech Republic
Contacts: phone [phone], e-mail: [email protected]
EEE group: 3 (IT and/or telecommunication equipment), Device use: indoor only
Power supply: 90-135 VAC, 2 A / 180-264 VAC, 1 A (50-60 Hz)
Working temperature range: 18 °C (PLA)-38 °C, indoor use only
Working humidity: 85 % or less
3 Multi Material Upgrade introduction
Multi Material Upgrade (MMU) is an addition to the Original Prusa i3 MK2/MK2S 3D printer
which enables printing with up to 4 different materials in one single print.
3.1 How it functions
Instead of traditional use of multiple independent extruders which is considered industry
standard, MMU uses only one hotend with 4 extruder motors and Y splitter. When the
material use is finished during the layer, it is pulled out of the hotend and next one is inserted
back in.
This removes any need to calibrate the position of the nozzle tips and reduces oozing or
artifacts. It is first commercial solution like this.

4 Software
Install the driver package from http://www.prusa3d.com/drivers/ and during installation,
select Original Prusa i3 MK2 Multi Material as one of the installed printers. Two additional
programs will be installed compared to the standard MK2/MK2S installation.
4.1 Prusa3D Slic3r Multi Material
When you open the Prusa3D Slic3r Multi Material you can immediately see few differences.
First you can see and adjust the position of Smart Wipe Tower (more info about how Smart
Wipe Tower works can be found in 9.1 Smart Wipe Tower size and additional print time)

marked as 1 on the picture and you can see 4 material select boxes marked as 2.
Material selectors have colored boxed on the left, by clicking on them you can assign color
to each extruder and preview the model in final colors when the model is sliced in Preview
tab.

4.1.2 Slicing profiles
Print profiles for 150um and 200um are preconfigured in the Slic3r PE for Multi Material.
Lower layer heights are not available yet, only when using single mode discussed in chapter
8 Printing in Single mode with one extruder.
Additional print settings and materials can be used on the Multi Material in single extruder
mode. Just install normal MK2 from Drivers package (when selection Original Prusa i3 MK2
Multi Material, everything is automatically pre selected) and select Multi Material Single
Mode from printer options. This will allow you to use Variable Layer Height and 100 um and
lower layer heights. The printer is as capable as regular MK2/MK2S in this mode so it can
print flexible materials etc without problems.
4.2 Multi Material post processor
Multi Material post processor is an application to generate Smart Wipe Tower and filament
switching into the g-code file for the MMU equipped printer. G-code generated with Multi
Material Slic3r already has those, (since drivers release v1.7.8.2) so post processor is not
needed, however when using ColorPrint g-code needs to be processed. Post Processor
will be also needed in the future to process g-codes from other slicing engines like
Simplify3D. Official support for 3rd party slicers hasn’t been released yet.

5 Supported materials
Currently only PLA, ABS, FLEX and PVA/BVOH (Primaselect PVA or Verbatim BVOH works
reliably) are supported in Multi Material mode. Normal range of filaments can be used in
single mode discussed at chapter 8 Printing in Single mode with one extruder. We're testing
and preparing settings for more. Combinations of different temperature materials are
possible, hotend can change temperature during the printing of Smart Wipe Tower.

Filaments which tend to be extremely stringy can however increase the chance of clogging
the Y splitter and require cleaning.
5.1 Filaments and print quality
Some filament are harder to print than others. If you are having troubles, try different brand
or color. From our experience chalky feeling filaments with mineral filler are not as
aesthetically pleasing. Same applies on MK2, but effect is multiplied with multi material
upgrade. Smooth and shiny looking filaments will produce the best results.
For some filaments or color combinations (such as black color together with white color)
additional wipe area might be needed. That can be set up in Multiple Extruders menu under
the Print Settings tab. Default value work with most materials and color combinations.
The better quality filament will yield much better results than low cost filament from ebay.
Good and well working brands are Prusa, Fillamentum, ColorFabb …
5.2 Loading/Unloading the filament
Always check filament before the print for potential damage, cut off all of the damaged part
to be sure that filament can pass extruder pulleys and cooling tubes properly. Pay special
attention to this after every aborted print.

Loading filament now has slightly changed behaviour compared to regular MK2 and always
load/unload it from menu.
When opening the Load or Unload menu, you have an option to Load/Unload all 4
automatically or each extruder separately.
First phase of automatic loading is slow feed (In this phase you just push the filament to the
entry hole of the extruder and as soon as you feel that the extruder grabs it, press the knob).
Second phase is fast feed (This phase just loads the filament to the cooling tube and
prepare it for the operation).
6 Upgrade and first print
1. Assemble the upgrade according to
http://manual.prusa3d.com/c/Original_Prusa_i3_MK2_to_Multi_Material_upgrade
2. Upgrade firmware to 3.0.12 or the newer from www.prusa3d.com/drivers Use the
Multi Material version placed in folder “MK2-MultiMaterial”
3. Install 1.7.8 drivers or newer with Prusa3D Slic3r MK2 Multi Material and Multi
Material postprocessor from www.prusa3d.com/drivers
4. Delete all files from your printer SD card. They are no longer compatible
5. Copy all sample g-codes from our driver package Objects/MK2MM folder to the SD
card.
6. Load filament. See the section 5.2 Loading/Unloading the filament
7. Run V2MM Calibration from SD card and run Live Adjust Z like on regular MK2
8. Print a sample g-code. Gear Bearing is a good start model
7 Printing in Multi Material mode
7.1 Loading the model in Slic3r Multi Material
Start by opening the main part of the model. In our example we use Chimera (it is copied to
your hard drive during the Drivers installation) and Chimera_6_body.stl. Load the file as if
printing with normal MK2 and double click the object afterwards. New dialog will open where
you can load additional parts.

Click Load parts..., select all additional files and Open.
Now you can easily highlight every part and set the extruder with which it should be printed.

Easier to follow video guide how to prepare the g-code files is available at
http://prusa3d.com/MMUVIDEO
7.2 Printing with soluble supports
We strongly suggest to use Verbatim BVOH support material. It is available on our eshop
http://shop.prusa3d.com/en/special/161-verbatim-bvoh-soluble-support-05kg.html or as a
second best option Prima Select PVA also available
http://shop.prusa3d.com/en/special/169-primaselect-pva-soluble-support-500g.html.
Unfortunately quality of different PVA brands vary greatly and we cannot guarantee anything
from other soluble support brands :-/
Soluble support material always needs to be selected in the extruder number 4 (the
rightmost one) and selected in Prusa3D Slic3r MK2 Multi Material as the fourth filament.
Special print setting 0.20mm NORMAL Soluble Supports needs to be used. Apart from this
change printing works as with regular multi material printer. Extruder 1 to 3 can be used as
usual.
NOTE: Water soluble supports always need to be stored in dry conditions.

8 Printing in Single mode with one extruder
Features like Smooth Variable Layer Height or finer print settings are not yet available in
Multi Material mode yet. But they can be used in Single mode with just one extruder
enabled. It makes the printer basically bowden version of MK2.
Simply launch Prusa3D Slic3r MK2 where additional printer config is available as “MK2
MultiMaterial single mode”.
When printing g-code generated like this, printer will ask you which extruder should be used
to print the object.
WARNING: The g-codes generated for normal MK2/MK2S will either not work at all or
produce very poor results. They need to be generated again.
8.3 Using web Color Print app
Slice the object as you are used to in Multi Material Single mode. Load the gcode into
http://www.prusaprinters.org/color-print/ and select Multi Material.
You can add color changes as you are used to, but you will be able to select to which
extruder printer will switch.
After downloading the .gcode, you need to use Multi Material Post Processor app to
generate wipe tower.
Please note, all used colors need to be the same material.

9 Frequently asked questions
9.1 Smart Wipe Tower size and additional print time
How big is the smart wipe tower?
Wipe tower is always 60 mm wide and contain between one and three 15 mm slots based on
the model you are printing. If you only two materials are printed at one layer, one slot is
used. Each additional material will add one slot and increase the size by another 15 mm.
One slots takes approximately 1 minute per layer.
In some prints, multiple materials during single layer are used later, but print starts with only
one. In this case the smart wipe tower is still being printed with number of slots from the
most complex part of the model. However, before those slots are actually used, they are
printed with sparse infill to save material. When slots are not needed anymore later in the
print, the number is automatically reduced. This is the reason it is called “smart”.

Smart wipe tower prevents the need to use any sort of ooze shields as in traditional multi
extruder systems! The size also remains constant, no matter how many copies of the objects
you print or how big the object is.

We suggest to print more copies of the same object, if printing small parts as the Smart Wipe
Tower will remain the same size.

10 Troubleshooting
In case of any problems, please first look here -
http://manual.prusa3d.com/c/Troubleshooting